1. Field of the Invention
The present invention relates to a vibration correcting device suitable for use in an optical apparatus, or a shooting device of, for example, a shooting apparatus.
2. Description of the Related Art
As a vibration correcting device, as in U.S. Pat. No. 6,208,377 and U.S. Pat. No. 6,233,009, there is a vibration correcting device including a frequency vibration detecting unit, which detects vibration frequency, and a vibration correcting unit. The vibration correcting device provides a suitable vibration correction effect by correcting a phase displacement of frequency characteristics.
In recent years, maintenance of information infrastructure or security has increased the necessity of setting shooting devices. Among such shooting devices, there is an increasing need for shooting devices that can be used for high magnification. In addition, there is an increasing need for a vibration correction function.
When a shooting device is set to, for example, a floor, a wall, or a ceiling, the shooting device may resonate at a frequency that is characteristic of the shooting device due to, for example, setting conditions or manufacturing errors of the shooting device. In particular, shooting devices provided with movable sections having pan/tilt driving mechanisms tend to resonate at their natural frequencies. Although the causes thereof depend upon the shooting devices, it may be said that there are various causes, such as the mass and rattling form in a gap of the movable section.
FIG. 3 shows the result of setting a shooting device, inputting various frequencies having the same amplitude, and measuring the vibrations of the shooting device. The horizontal axis represents the frequency, and the vertical axis represents the amplitude. From FIG. 3, it can be understood that, when the input has a certain amplitude, the amplitude of the shooting device increases at a predetermined frequency. This means that the amplitude of the vibration of the shooting device is increasing with respect to the vibration at this frequency. It may be said that resonant frequency corresponds to the aforementioned natural frequency. In general, for example, ceilings are places where vibration is low. However, they are not places that do not vibrate at all. That is, they may undergo very small vibrations having various frequency components. It is known that, when a shooting device having a resonance characteristic is set, the amplitude of the vibration of the shooting device increases at a certain natural frequency, thereby causing an image to become blurred.